Table 1.
Patients' demographics and clinicopathological characteristics.
| Characteristics | Total cohort | Training cohort | Validation cohort | P value |
|---|---|---|---|---|
| 2,451 (100%) | 1,715 (70.0%) | 736 (30.0%) | ||
| Age | 0.627 | |||
| <65 | 947 (38.6%) | 668 (39.0%) | 279 (37.9%) | |
| ≥65 | 1,504 (61.4%) | 1,047 (61.0%) | 457 (62.1%) | |
| Race | 0.605 | |||
| White | 1,984 (80.9%) | 1,384 (80.7%) | 600 (81.5%) | |
| Black | 351 (14.3%) | 245 (14.3%) | 106 (14.4%) | |
| Other | 116 (4.7%) | 86 (5.0%) | 30 (4.1%) | |
| Marital status | 0.121 | |||
| Married | 1,619 (66.1%) | 1,126 (65.7%) | 493 (67.0%) | |
| Unmarried | 700 (28.6%) | 505 (29.4%) | 195 (26.5%) | |
| Unknown | 132 (5.4%) | 84 (4.9%) | 48 (6.5%) | |
| Histology | 0.518 | |||
| Ductal | 2,264 (92.4%) | 1,588 (92.6%) | 676 (91.8%) | |
| Lobular | 23 (0.9%) | 16 (0.9%) | 7 (1.0%) | |
| Mixed ductal and lobular | 45 (1.8%) | 34 (2.0%) | 11 (1.5%) | |
| Others | 119 (4.9%) | 77 (4.5%) | 42 (5.7%) | |
| Grade | 0.223 | |||
| I | 305 (12.4%) | 210 (12.2%) | 95 (12.9%) | |
| II | 1,294 (52.8%) | 903 (52.7%) | 391 (53.1%) | |
| III | 848 (34.6%) | 601 (35.0%) | 247 (33.6%) | |
| IV | 4 (0.2%) | 1 (0.1%) | 3 (0.4%) | |
| AJCC stage | 0.289 | |||
| I | 861 (35.1%) | 597 (34.8%) | 264 (35.9%) | |
| II | 1,038 (42.4%) | 724 (42.2%) | 314 (42.7%) | |
| III | 403 (16.4%) | 296 (17.3%) | 107 (14.5%) | |
| IV | 149 (6.1%) | 98 (5.7%) | 51 (6.9%) | |
| Bone metastasis | 0.398 | |||
| Yes | 112 (4.6%) | 74 (4.3%) | 38 (5.2%) | |
| No | 2,339 (95.4%) | 1,641 (95.7%) | 698 (94.8%) | |
| Brain metastasis | 0.070 | |||
| Yes | 6 (0.2%) | 2 (0.1%) | 4 (0.5%) | |
| No | 2,445 (99.8%) | 1,713 (99.9%) | 732 (99.5%) | |
| Liver metastasis | 0.301 | |||
| Yes | 17 (0.7%) | 10 (0.6%) | 7 (1.0%) | |
| No | 2,434 (99.3%) | 1,705 (99.4%) | 729 (99.0%) | |
| Lung metastasis | 0.039 | |||
| Yes | 56 (2.3%) | 32 (1.9%) | 24 (3.3%) | |
| No | 2,395 (97.7%) | 1,683 (98.1%) | 712 (96.7%) | |
| ER status | 0.789 | |||
| Positive | 2,383 (97.2%) | 1,666 (97.1%) | 717 (97.4%) | |
| Negative | 68 (2.8%) | 49 (2.9%) | 19 (2.6%) | |
| PR status | 0.574 | |||
| Positive | 2,229 (90.9%) | 1,556 (90.7%) | 673 (91.4%) | |
| Negative | 222 (9.1%) | 159 (9.3%) | 63 (8.6%) | |
| HER2 status | 0.507 | |||
| Positive | 284 (11.6%) | 207 (12.1%) | 77 (10.5%) | |
| Negative | 2,088 (85.2%) | 1,454 (84.8%) | 634 (86.1%) | |
| Borderline | 79 (3.2%) | 54 (3.1%) | 25 (3.4%) | |
| Surgery | 0.753 | |||
| Yes | 2,310 (94.2%) | 1,618 (94.3%) | 692 (94.0%) | |
| No | 141 (5.8%) | 97 (5.7%) | 44 (6.0%) | |
| Radiotherapy | 0.679 | |||
| Yes | 670 (27.3%) | 473 (27.6%) | 197 (26.8%) | |
| No | 1,781 (72.7%) | 1,242 (72.4%) | 539 (73.2%) | |
| Chemotherapy | 0.686 | |||
| Yes | 911 (37.2%) | 633 (36.9%) | 278 (37.8%) | |
| No | 1,540 (62.8%) | 1,082 (63.1%) | 458 (62.2%) | |
| Median follow-up time (Months, 25th−75th percentile) | 27 (12–46) | 27 (13–45) | 27 (12–49) | 0.735 |
AJCC, The American Joint Committee for Cancer; ER, Estrogen receptor; PR, Progesterone receptor; HER2, Human epidermal growth factor 2-neu.